The present invention relates to a burner of the external mixing type. In particular the present invention relates to a burner exhibiting excellent flame stability.
The treatment of some industrial waste by incineration in oxygen is currently regarded as a very promising operation. The waste, in the form of a gas, a liquid or a foam, possibly containing suitable additives, is sent into a burner fed with pure oxygen or a gas with at least a high oxygen content.
For example, a process is known which has been developed for treating certain aqueous effluents coming from the flushing of steam generators of nuclear power stations, but which may also have many other applications. This process comprises dispersing the waste to be incinerated in an aqueous solution containing a surfactant and, where appropriate, a fuel, converting this solution into a slightly pressurized foam and transferring this foam into a cyclone furnace where it is passed through an oxygen burner.
The advantages of using oxygen in a burner are well known, among which are the possibility of obtaining high temperatures, good retention of the flame at the nozzle of the burner, even for low calorific values, a decrease in the volume of flue gases and, consequently, in the overall size of the plant, and a reduction in the product ion of nitrogen oxides.
In order to limit the drawbacks resulting from the variations in composition of the material to be treated, which is the general rule in the case of waste, it is preferable to use a burner having external mixing. However, studies have shown that the currently available burners of this type do not allow sufficient flame stability to be achieved in the case of large variations in the material to be treated.